The JBnator Diaries – How to free 70MB RAM on 2G/3G iPhones

As I promised in my iDevice overclocking article, I will tell you how to free RAM on your Jesus device. As most of you probably know limited RAM is THE iDevices most limiting factor today and the reason for most app crashes. The iPhone OS tracks the amount of free memory available and starts killing off background apps when it gets low (remember, even on the the OS 3.0 Apple’s stock apps like Mail, Safari and iPod still support backgrounding out of the box). If the memory still gets under a certain threshold the OS kills the running app as well.

Well, the jailbreaking community has an answer to this, as it turns out. And the funny thing is – it is an age old technology, present in the desktop OSs for years. I’m talking of course about Virtual Memory.

Different to the iPhone OS, desktop OSes are not limited by the physical amount of RAM they have available. On the contrary – they have a special paging files on the harddrive where information can be swapped around. Of course, this ‘paging’ has a significant impact on performance, but it also allows more software to be churned through.

On iPhone OS, the available tweaks work the same way – they create a paging file and a special daemon that handles the paging. But this, of course, comes at a price of much longer load times and occasional slowdowns while the swapping is being done. Quite a variety of such tweaks exist. Probably the most well-balanced is the SuperCharged tweak by ibnyaffa. On an iPhone 3G it gives me an average of 60-70 MB extra RAM. Without it, I average about 30MB.

A note of warning – using this tweak WILL SHORTEN THE LIFE of your iDevice. As noted above the tweak involves constant swapping of the RAM to and from the internal storage of the iPhone, which is built on a NAND flash technology and has limited read/write cycles. I won’t go into the details, but constantly using this tweak will shorten the life of your iDevice by about 3-4 years. If you ain’t scared, read on.

Disclaimer: Proceed at your own risk. Neither I nor TouchMyApps.com will not accept any responsibility for any damages to you iDevice, the data stored on it or your personal well-being should you follow this guide.

Now you can activate it either via the Free Memory option in SBSettings or assign a custom gesture to it (MemoryTap) in Activator.

If you wish to uninstall the tweak – simply find it in Cydia Packages and tap Remove. Make sure to manually delete the SuperCharged folder from /var afterwards as well.

Personally I can say I have toyed around with for a few days, but ultimately decided I was better off without. Yes, it does give the RAM and I can have much more apps running simultaneously in the background. But the increase of the loading times is so frustrating that I decided to stick with the two tweaks I will cover in my following articles.